1. Field of the Invention
The present invention relates to a fisheye correction method and related image processor, and more particularly to a fisheye correction method and the related processor for saving memory space, reducing perspective distortion and allowing user's intervention during the fisheye image restoring process.
2. Description of the Prior Art
As the digital image processing technology improves, the images taken by fisheye cameras has been able to be processed in real time, and presented to the user instantly such that the user can interpret the image contents for various purposes. For example, in applications like the back up camera in a car rear view system, the door phone system of a building and the surveillance camera in a security system, the fisheye cameras and the associated image processing system are getting more widely used. Besides that, images taken by a fisheye camera and stored in the digital storage devices can also be retrieved, processed, restored by a similar method, and then presented to the user.
Since a fisheye camera can collect a large viewing angle of image information, the picture taken by the fisheye camera has been distorted and squeezed such that the ordinary user is often being confused while reading the fisheye distorted image, and the contents of the image are hard to interpret correctly. If the fisheye distorted image is not processed properly before presented to the user, it is also possible for an ordinary user to miss important information in the image. Therefore, having a digital image processing device to have the fisheye distorted images restored before they can be presented to the user becomes the most widely accepted solution.
However, the fisheye image restoring method of the prior art needs large memory space to store the intermediate results. Therefore, the cost for realizing the image processing device is relatively high. Meanwhile, the restored image of the prior art suffers from perspective distortion, which introduced problems of non-uniformity of the object size in the picture, and can increase the difficulties of interpreting the images.